4. Carry a sweater or jacket to avoid a chill because temperature changes can cause allergy flare-ups. Also, don't indulge in iced drinks. "When you have allergies, your body's thermostat is off," Grossan says. "Instead of providing blood to the skin to warm it, the lack of temperature regulation causes you to sneeze and hack." The chilling of your body also slows the cilia, which worsens allergy symptoms.